Saturday, March 2, 2019

Filing your mouth

I got my older Stanley 5 1/2 some years ago in poor condition.  I rehabbed it to be a user and it has worked very well but there was always an issue that I knew I would have to face someday:  there was substantial pitting on the back of the blade that would end its useful life prematurely and that is what happened last week.

Pre-1939 5 1/2s have an unusual 2 1/4" blade, so it's difficult to find a replacement.  I ordered a replacement blade and chip breaker from Ron Hock but, when it arrived, it wouldn't fit.  Basically, the blade was too thick to fit through the mouth.  When you retracted the frog enough for it to fit, the blade would ride up on the back of the mouth (the frog was positioned behind it).  I called Ron on a Saturday and he called me back promptly.  There is one type that has this problem.  He offered to take the blade and chipbreaker back or to instruct me on filing the back of the mouth to make it fit if I was willing to.  I was hesitant about my ability to do it well but he assured me that it isn't too difficult, so I gave it a shot.  The back of the mouth is vertical and you basically file the top back closer to the angle of the frog.  I did it, it worked, and the plane performs beautifully.

There's a philosophical question about whether you should be modifying a vintage Stanley plane and I understand that some might not want to but I don't know what the alternative is.  I am not aware of a thinner replacement blade in this unusual size.  Lee Valley, for example, doesn't offer them.  I have a Hock blade in my #7 and I like it.  This is a user that I got at a garage sale for $20, rusted and covered with grime.  As far as I understand, my modification wouldn't interfere with using an original blade if I ever found one, which is highly doubtful.  To me, it is better to have a tool that is in excellent working condition as a result of a modest modification than to have an original sitting on the shelf.  Hey, some of my friends have replacement knees and they're still their same old cantankerous selves.  Still original even though they've been modified.


  1. She is a sweet looker. There is a place in England that sells 2 1/4 irons (thinner then hock). I got one from them, It is thicker than the Stanley but less than the Hock and I didn't have to file the mouth. I lost the URL when my computer crashed but I'll search for it. Once I find it I'll send it.

  2. Andy,

    No knees yet but cantankerous yes :-). Looking around my shop you might think I was a collector just because of the numbers but the truth is they are all users and many with replacement irons and other mods. My preference is a "thin" cutter like the OEM Stanley but it is getting harder to find clean ones.

    Out of curiosity brought on by your post I did a rough measurement of some ot the cutters in my users. The thinnest was no surprise the Stanley pre-war measured 2.1mm. Next was a Hock O1 at 2.4mm with a Ray Iles O1 at 2.6mm. A Japanese laminated iron and a LV O1 both measured 2.7mm and of course the big huker of the bunch was a LN A2 at 4.2mm.

    What does it all mean, I haven't a clue other than I dislike the LN iron. I'm not sure if it is the A2 or the weight but whatever all my LN planes have replacement iron mostly LV O1 because that is the only one that fits with just a little modification to the frog or the cap iron.

    BTW, your 5 1/2 looks like a great user. It is hard to go wrong with a Hock iron. I've talked to Ron about making a O1 replacement iron for LN planes but dropped the idea because the cap iron mod is so easy.


    1. Hi Ken,
      I too have disliked A2 steel. I use the Paul Sellers diamond sharpening method (coarse, fine, superfine). What helped me tremendously was adding an extra extra coarse plate to start with for A2. That way, I can get a burr in a more reasonable time frame.

  3. I'm with you on O1. I think it is easier to sharpen and takes a better edge and these benefits more than offset needing to sharpen it sooner.

  4. I found it Andy. Moot point as you filed it already but it will fit the Stanley without surgery.

  5. If you make a few things that bring pleasure to friends and family it is worth more than setting another non-functional Stanley on the shelf to go in the woodworking museum when, God forbid, there is no more wood to plane.

  6. As a long time collector and user, I have no problems modifying my tools to make then functional again.. depending mostly on its rarity. The usual Stanley's bench planes are plentiful and enough have been preserved, go ahead mod it and enjoy your tool new lease on life

    Bob, who has a 'few' tools to commiserate over :-)

  7. Ken,

    It's nice to hear from you. Yes,I am fine. For a variety of reasons, I stopped woodworking for a year. We moved to a small ranch in central Oregon with irrigated pastures for three horses that the previous owner left. I will be posting about this as some point but, long story short, the buyer of our previous house made a good offer contingent on me leaving the many items of furniture I had made so I'll be back doing a lot of woodworking this fall.

    I read your blog often.